Alternating-current transformer.



No. 739,004. PATENTBD SEPT. 15, 1903. D. O. JACKSON. ALTERNATING CURRENT TRANSFORMER.

APPLICATION FILED SEPT. 29. 1900.

N0 MODEL.

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Patented September 15, 1903.

PATENT OFFICE.

DUGALD G. JACKSON, OF MADISON, XV ISCONSIN.

ALTERNATlNG-CURRENT TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 739,004, dated September 15, 1903.

Application filed September 29.1900- Serial No. 31,472. (No model.)

To all "whom it Hui/y concern:

Be it known that I, DUGALD C. JACKSON, a citizen of the United States, residing at Madison, in the county of Dane and. State of Wisconsin, have invented certain new and useful Improvements in Alternating-Current Transformers, of which the following is afull,

Heretofore it has been possible to transform alternating currents of constant pressure to constant current through the agency of static transformers specially provided with a leakage path or paths for the lines of force generated by the primary circuit. Such transformers may be used for transforming currents up to certain limits, it being obvious that when the angle of lag thereof becomes ninety degrees it is impossible for the transformer to do work. An exact regulation, therefore, cannot be efiected without modifying mechanism. Such transformers are therefore not convenient for ordinary use in commercial arc-lighting or any other branches of electrical transmission in which a constant current may be utilized. constant-current transformers have also been employed in which coils relatively movable along a common core are employed. In these latter transformers, however, the inducingwinding was simply a single-phase-current coil.

It is the prime object of my present invention so to arrange the windings of a static transformer and'to arrange the cores aboutwhich the said windings are placed that exact regulation may generally be effected under all conditions of lag or load. To this end I provide, generallyspeaking, in the preferred embodiment of my invention a core for the primary of the said transformer and windings wound about said core, the whole being similar to the core and winding of the ordinary Other kinds of Y induction motor-field winding. I provide a secondary in inductive relation to said primary, which preferably consists of an ordinary alternating-current-generator armature'winding, preferably placed upon a suitable core, the said winding consisting of one or more circuits adapted for inclusion with one or more external circuits. In order to facilitate regulation, I preferably mount the said secondary winding so that it is adapted .to slide into and out of closed inductive relation to said field-windings, the said secondary winding being preferably non-revoluble relative to the field-windings. I preferably provide means for counterbalancing the tendency of the secondary winding to move out of inductive relation with the field-windings. Through the agency of these means the device of my present invention is practically selfregulating and transforms a current of con-- stant potential impressed upon the circuit into one or more alternating currents of constant current in the secondary, the magnetic relations existing between the secondary and the primary being such under the conditions stated that a constant pressure impressed on the primary will produce a constant current in the secondary, or vice versa.

I will explain my invention more in detail by reference to the accompanying drawings, illustrating the preferred embodiment thereof, in which-- Figure 1 is a diagrammatic view of a trans former constructed in accordance with my invention. Fig. 2 is a side view thereof, showing the means employed for governing the sliding tendency of the secondary winding.

Like characters of reference indicate like parts throughout the views.

In the drawings I have shown a source of current l as impressing two-phase alternating currents upon the circuit 2. I include my improved transformer 3 in circuit with the said circuit 2. The transformer 3 preferably consists of a field-ring at, provided with suitable. energizing-coils 5 5 and 66, respectively, included in opposite branches of the circuit 2, the windings, together with the source of energy as at present illustrated, producing two field-poles in the field-ring 4, it being of course obvious that a similar result may be obtained through a single-phase source of energy provided with means for splitting phase or'that alarger number of poles may be employed, if desired. I employ a secondary comprising coils 77 in inductive relation to the said primary field-windings 5 5 and 6 6. 'I preferably construct this winding according to the ordinary drum-wound armature-windings of alternators, the winding in this instance being illustrated "as adapted for a two-pole field, the coils all being connected in series, collector-rings not being necessary in'this instance, as the said coils 7 7 are not adapted to revolve. I provide a coreS for the said coils 7 7, the said coils being preferably mounted upon the surface thereof,but covering'only a portion of the total surface thereof, sectors..9 9 being preferably placed thereon, together with the said coils, to form an unbroken surface for the completed secondary, or the coils may be wound in slots in the core. I preferably mount the core 8 upon a stationary shaft 10, a pin 11 preventing the revolution of the core 8. As has'been stated heretofore, all the coils 7-7 are in series in this instance, in which I have shown the secondary as comprising but a single circuit, the said coils being included with the external circuit 12 12, comprising the ordinary commercial constant-currentarc-lamps 13 13 herein diagrammatically shown.

Referring more particularly to Fig. 2, I have shown a partial sectional view through the machine, in which the shaft 0 is non-rotatably mounted in suitable bearings 14 14, placed at opposite ends thereof. A change of load due to the cutting in or out of circuit 'of'arc-lamps l3 13 from the secondary circuit necessitates a change of voltage to conform to the new current conditions. The machine of my present invention, however, has an inherent tendency to regulate and compensate for such changes, inasmuch as with a change of load the secondary winding tends to move into and out of'closed inductive relation with the field-coils"; I therefore construct the bearings 14 14in such manner that the sliding friction thereof will be a very slight quality, so that very little friction will impair the longitudinal movement of the secondary winding. In order, however, to bring the secondary winding back into inductive relation with the field, asrwhen an increased nu mber of lamps are included in the circuit, I preferably provide a spring 15 of sufficient strength to place the secondary winding back into its normal position centrally located with respect to the field-core. It is obvious that this longitudinal sliding motion of the secondary winding with respect to the primary fieldcoils would have an injurious effect upon the power factor of the machine, inasmuch as the receding ofthe iron core carrying the secondary coils from under the influence of the primary lines of force would cause an unnecessary flow of the magnetizing-current. In order to obviate this diffivsaooa culty, I provide a blank core of magnetic material 16 at one end of the armature and rigidly secured thereto, which core is adapted to move into and out of magnetic relation with the field-coils accordingly as the secondary coils of the apparatus are displaced upon changes of load.

It will be understood that the self-regulating qualities of the machine are not impaired if the armature is revolubly mounted, as a longitudinal displacement of the revoluble armature may take place, the only diiference being that there will be a change in frequency due to rotation of the said armature, so that a change of load would cause a change of speed of the armature, and thus vary the frequency. If the machine is to be used in connection with arc-lamps, such change in the frequency is not detrimental to the satisfactory operation thereof.

I do not wish to be limited to the number of phases employed in the primary circuit nor to the number of secondary circuits" into which the. said primary currents are transformed. I have herein shown and particularly described one embodiment of my invention; but it is obvious that many changes and modifications may readily be made without departinglfrom the spirit thereof.

I therefore claim as newand desire to'secure by Letters Patent 1. An alternating current transformer, comprising primary windings for creating a rotating field, asecondary winding in inductive relation with said primary winding, acore upon which said secondary winding is wound, and means for effecting longitudinal movement of said core upon changes of current in the secondary winding, whereby a relative longitudinal displacement is caused between the said primary winding and the said secondary winding carried by said core, substantially as described.

2. An alternating current transformer, comprising primary windings for creating a rotating field, a secondary winding in inductive relation with said primary winding, a core upon which said secondary winding is wound, and automatic means for effecting longitudinal movement of said core upon changes of current in the secondary winding, wherebya relative longitudinal displacement is caused between the said primary winding and the said secondary winding carried by the core, substantially as described.

3. In an alternating-current transformer, the combination with a primary winding adapted for inclusion with a constant-potential circuit for creating a rotating field, of a secondary winding in inductive relation with said primary winding, a core upon which said secondary winding is wound, and means for efiectinga longitudinal movement ofsaid core upon changes of current in said secondary winding, whereby a relative displacement is caused between said primary winding and said secondary winding upon said core wherelbs secondary winding, whereby a relative displacement is caused between the said primary winding and said secondary winding upon said core whereby a constant current is generated in said secondary winding, substantially as described.

5. In an alternating-current transformer, the combination with primary field-coils for creating a rotating field, of a secondary winding comprising coils in inductive relation with said primary coils, a core upon which said secondary coils are stationarily mounted, and

means for causing a longitudinal movement of said core whereby a relative displacement is caused between said primary coils and said secondary coils carried upon said core, substantially as described.

6. In an alternating-current transformer, the combination with primary field coils adapted for inclusion with a constant-potential circuit and adapted to create a rotating field, of secondary coils in inductive relation with said primary coils, a core upon which said secondary coils are stationarily mounted, and means for causing a longitudinal movement of said core, whereby alongitudinal displacement of said secondary coils with respect to said primary coils is caused, whereby a constant current is maintained through the secondary coils, substantially as described.

7. In an alternating-current transformer, the combination with primary field-coils, of secondary coils in inductive relation therewith, an armature-core upon which said secondary coils are wound, and means for efiecting longitudinal movement of said armaturecore upon changes of current through said secondary coils, whereby a relative longitudinal displacement is caused between the secondary coils and said primary coils, substantially as described.

8. In an alternating-current transformer, the combination with primary field coils adapted for inclusion with a constant-potential circuit and adapted to create a rotating field, of secondary coils in inductive relation with said primary coils, an armature upon which said secondary coils are statiouarily wound, and means whereby to effect a longitudinal movement of said armature-core upon changes of current through the secondary coils, whereby the inductive relation between said secondary coils and said primary coils is varied to maintain a constant current through said secondary coils, substantially as described.

9. In an alternating-current transformer, the combination with a field-core, of primary windings upon said core adapted for inclusion with a constant-potential circuit and adapted to create a rotating field, an armature-core disposed within said field-core, secondary windings upon said armature-core, and means for effecting a longitudinal displacement of said armature-core with respect to said field-core upon changes of current through said secondary windings, whereby the inductive relation between said secondary windings and said primary windings is Varied to cause a constant current to flow through said secondary windings, substantially as described;

10. In an alternating-current transformer, the combination with a field-core, of primary windings upon said core adapted for inclusion with a constant-potential circuit and adapted to create a rotating field, an armature-core disposed within said field-core, secondary windings upon said armature-core, means for effecting a longitudinal displacement of said armature-core with respect to said field-core upon changes of current through said secondary windings, whereby the inductive relation between said secondary windings and said primary windings is varied to cause a constant current to flow through said secondary windings, and a blank armature-core adapted to replace the armaturecore carrying the secondary windings upon longitudinal displacement thereof, substantially as described.

11. In an alternating-current transformer,

the combination with a field-core, of primary windings upon said coreadapted for inclusion with a constant-potential circuit and adapted to create a rotating field, an armature-core disposed within said field-core, secondary windings upon said armature-core, spring mechanism for effecting longitudinal displacement of said armature-core with respect to said field-core upon changes of current through said secondary windings, whereby the inductive relation between said secondary windings and said primary windings is varied to cause a constant current tofiow through said secondary windings, and a blank armature-core adapted to replace the armature-core carrying the secondary windings upon longitudinal displacement thereof, substantially as described.

12. In an alternating-current transformer, the combination with primary field coils adapted for inclusion with a constant-potential circuit, and adapted to create a rotating field, of secondary coils 7 7 in inductive relation therewith, means for causing a relative displacement longitudinally between the said secondary coils and the said primary coils, and'a core 8 for said secondary coils, substantially as described.

13. An alternating-current transformer comprising primary windings for creating a rotating field, of a secondary winding in in- ICO ductive relation with said primary winding, means for effecting a movement between the said primary and secondary windings, and a magnetic core 16 for taking the place of the secondary windings when relatively displaced from closed inductive relation with the said primary windings, substantially as described.

14. An alternatingcurrent transformer comprising primary windings for creating a rotating field, a secondary winding in inductive relation with said primary winding, a magnetic core 16 for taking the place of the secondary winding when relatively displaced from closed inductive relation with the said primary winding, and means for causing a relative longitudinal displacement between the said primary and secondary windings,

substantially as described.

15. In an alternating-current transformer, the combination with primary field-coils adapted for inclusion with a constant-potential circuit, and adapted to create a rotating field, of secondary coils 7 7 in inductive relation therewith, means for causing a relative displacement longitudinally between the said secondary coils and the said primary coils, a core 8 for said secondary coils, and a shaft 10 upon which said core is mounted, substantially as described.

16. In an alternating-current transformer, the combination with primary windings distributed about the field-frame, adapted for inclusion with a constant-potential circuit and adapted to createa rotating field, of secondary coils 7 7 in inductive relation therewith, a core 8 for said secondary coils, an auxiliary core 16, and. means for effecting a relative longitudinal displacement between the said windings, substantially as described.

In witness whereof I hereunto subscribe my name this 20th day of September, A. D. 1900.

DUGALD C. JACKSON.

Witnesses:

MAX W. ZABEL, CHAS. E. HUBERT. 

